A web from which may be punched diaper closure elements has an elastically stretchable region and inelastic connecting regions for attaching to a diaper as well as for connecting a closure part. With the method on which the invention is based, parallel and spaced-apart film strips of an elastically extensible polymer are laminated between two tapes of nonwoven material.
DE 10 2004 035 649 relates to a method with the above-described characteristics for making diaper closure elements. Between the elastic film strips the nonwoven tapes are glued directly to each other. The diaper closure elements punched from the web each have an elastically stretchable region and adjoining connecting regions on both ends of the nonwoven material. The diaper closure elements may be formed as short straps or may be in the form of so-called diaper ears whose connecting regions to a diaper are longer than the connecting region for fastening the closure part. Large forces are transmitted to the diaper closure elements via the closure part. For uniform introduction of forces into the diaper closure element it is advantageous to have a bending-resistant connecting region of high tensile strength. Furthermore it must be ensured that the connecting regions made of nonwoven material do not become frayed or permanently stretched if during use the diaper closure elements are stretched up to the elongation limit of the elastic region.
EP 1,252,015 describes a diaper closure element where the core layer is an elastic film that has nonwoven layers laminated to both its faces. The nonwoven layers and the core layer have the same external dimensions, i.e. the elastic core layer is as long in its stretch direction as the nonwoven layers laminated onto it on both faces. Both the connecting region for the closure part and the connecting region for fastening to a diaper are stiffened by a layer of inelastic polymer. Stiffening is accomplished by a tension-resistant film of for example polypropylene homopolymer that is laminated between the elastic film and one of the two outer layers in the connecting regions and that counteracts the elasticity of the elastic core layer. Since elastic polymers are expensive, there is a need for keeping the elastic polymer content in the bond as low as possible without disadvantageously affecting the elasticity and the mechanical properties of the bonding material.
U.S. Pat. No. 6,255,236 discloses a diaper closure element comprising a support with elastic and inelastic regions. The support, in particular, consists of a coextruded film with an elastic core layer and inelastic outer layers. A textile web is laminated onto one face of the support. The other face of the support has a closure part attached to it. Due to localized stretching that causes the inelastic outer layers of the support and the laminated-on nonwoven material to be overstretched in some regions, an elastically stretchable region is created. This is called selective mechanical activation. Here also it is disadvantageous that the elastic support extends over the whole length of the diaper closure element including the inelastic connecting regions. Another disadvantage is that the diaper closure element has a textile surface on one face only.
U.S. Pat. No. 6,875,710 describes a diaper closure element comprising a textile support consisting for example of nonwoven material. In specified regions the support is reinforced by a strip or layer of inelastic polymer applied in a thermoplastic state and at least partially permeating the fibrous structure of the nonwoven layer. In another region spaced therefrom, the support has a coating consisting of a thermoplastic elastomer that at least partially also permeates the fibrous structure of the nonwoven material forming an elastically stretchable region. The inelastic and elastic regions are spaced from one another. Due to the spacing, the transmission of forces between the reinforced or stiffened inelastic regions and the elastic region is unsatisfactory. If the material is stretched up to the elongation limit of the elastic region, there is a risk that the material between the elastic region and the inelastic regions consisting exclusively of nonwoven material is permanently deformed and destroyed.